A 6-substituted-5,6-dihydro-2-pyrone from Cryptocarya strictifolia

Total Synthesis of (+)‐Cryptocaryalactone and of a Diastereoisomer of (+)‐Strictifolione via Ring‐Closing Metathesis (RCM) and Olefin Cross‐Metathesis (CM)

“…phase was washed with 1m aq. HCl and brine (1 Â 20 ml), dried (Na 2 SO 4 ), and concentrated, and the crude product purified by CC (SiO 2 ): 4 (0.63 g, 89% 4 (0.065 g, 0.598 mmol) was added, and the mixture was stirred at 08 for 30 min. Then the reaction was quenched with sat.…”

“…Moreover, it has been shown that the unsaturated moiety plays an essential role in the biological activity, due to its potential to act as a Michael acceptor in the presence of protein functional groups [2]. Cryptocaryalactone (¼ (6R)-6-[(2S,3E)-2-(acetyloxy)-4-phenylbut-3-en-1-yl]-5,6-dihydro-2H-pyran-2-one; 1) [3] and (þ)-strictifolione (¼ (6R)-6-[(1E,4S,6S)-4,6-dihydroxy-8-phenyloct-1-en-1-yl]-5,6-dihydro-2H-pyran-2-one; 2) [4] are such natural products showing a wide variety of activities.…”

Antiprotozoal Activity of &#945,&#946-Unsaturated &#948-Lactones: Promising Compounds for the Development of New Therapeutic Alternatives

“…Rugulactone (8) inhibits NF-KB activation pathway [22]. Lactones 9 [23] and 10 [24], as well as massoilactone (11) [25] and strictifolione (12) [26] have shown antifungal activity. Pectinolides A-C (13) exhibit significant antimicrobial and cytotoxic activity [27].…”

The Stereoselective Total Synthesis of (6S)‐5,6‐Dihydro‐6‐[(2R)‐2‐hydroxy‐6‐phenylhexyl]‐2H‐pyran‐2‐one via Prins Cyclization

“…Some of these compounds such as fostriecin [3] and goniothalamin [3] are known to display anticancer properties, and (À)-pyronetin [4] is known to exhibit immunosuppressive activity. Passifloricin-A [5] and strictifolione [6] are found to exhibit antifungal activity. (6S)-5,6-Dihydro-6-[(2R)-2-hydroxy-6-phenylhexyl]-2H-pyran-2-one (1) is also one such natural product which is known to exhibit antifungal activity against phytopathogenic fungus Cladosporium cucumarinum ( Fig.…”

“…-The synthesis of the natural product 1 started with chiral homoallyl alcohol 4 (Scheme 2). The precursor 4 was prepared in two steps by Cu I -mediated regioselective opening [11] of (À)-(R)-2-[(benzyloxy)methyl]oxirane (6) with vinyl magnesium bromide, followed by subsequent reductive cleavage of benzyloxy alcohol 7 with Li in liquid NH 3 . The Prins cyclization of 4 with 5-phenylpentanal (5) in the presence of TFA (10 equiv.…”